Beiträge von pe1chl

    This weekend my StarCom SR-3604 arrived, the 4-output version that I ordered intending to convert it to use an external reference.

    Because the housing has 4 F connectors, it will be easy to use one for the reference input, and have 3 outputs for the Phase4A receiver and my normal satellite settopbox (2 tuners).

    Now I opened it, I have seen something interesting: there are actually 2 separate 2-output legs in this device, each with a PLL/mixer chip of type "1051" (I have not found anything about it yet) sharing a single unmarked crystal (probably 25MHz like the marked one in the SR-3602).

    I'm going to try to convert one leg to use the external reference and a single output, and keep the other leg on the crystal. So I can watch TV without the reference connected.

    (there are 4-output PLL/mixer chips as well but apparently they did not decide to use one of those)

    Same idea over here when I installed the dish in the summer... and it turned out to be a good idea to be able to check what's going on at 24°E before going to 26°E :)

    ..and who knows what will come after XMAS.. perhaps an Es'hail-3 ? :/;)

    I have had this setup for over 20 years. Long ago I could receive a lot of programmes and feeds even on 58w there was a beam towards europe, on 43w there were a lot of transatlantic feeds, also on 22w and 15w. There even has been an ATV transmission on 16e (PI6ALK) and of course random interesting things like Dr Dish, daily live relays of the late show wth David Letterman, etc.

    Most of it is gone, but I still use my dish a lot e.g. to receive BBC/ITV on 28.2e, German programmes at 19.2e etc. And now to receive Es'hail-2 :-)

    I receive it with an unmodified StarCom SR-3602 LNB and an SDRplay RSP1a.

    An RTL stick should show similar receive sensitivity.

    Is it an el-cheapo plastic one or the RTL-SDR.COM device in metal case?

    Those I am certain to work at that frequency, the plastic ones may get a little hot.

    To align the antenna connect a DVB-S receiver and tune for some FTA channel on Astra 3A. (23.5E)

    With all WiFi equipment (filters but also antennas) you always need to watch for the maximum rated power. These devices are normally used at 100mW..1W EIRP so very low transmit power. Of course there exist illegal power amplifiers but even those are usually not more than 4W.

    I don't have an amplifier yet, more or less I am waiting for an opportunity to buy either some surplus PA or a design from LZ5HP (sg lab) if it becomes available.

    But also I am not that eager to get on as the first one, and like to see what the realistic power requirement will be. For now I have 2W and an 88cm dish for which I still need to make a feed.


    The Spectrian amplifiers are cheap but they are extremely inefficient!

    Not bad when you need a heater, but as a 13cm amplifier... not so good.

    It means a big power supply is required. And maybe that much power is not needed at all, we need to see.

    At the moment (21:52 UTC) I have both the 10.706 beacon (with modulation) and the 11.205 beacon (but without PSK modulation) at the usual strength.

    This is at V polarisation but I think the beacons are RHCP so that should not matter.


    I don't have so many of those spurious lines, the empty spaces look like clean noise here, nothing inside the transponder band that I would mistake for a transmission.

    My experience with a freerunning StarCom SR-3602 PLL LNB so far is that it is acceptable for "amateur SSB use" under quiet weather (and hand-on-dial) but when it is rainy/windy or when it is sunny and the sun has just raised or set, not so good.

    Of course it is good for first tries. And I just received my 4-output LNB that I will convert to external reference.

    Is that an SDR-based software approach? There is that idea of locking the SDR to a carrier within the received band that is known to be stable. The beacons could be used for that purpose (after removing the BPSK modulation of course).

    The user would then see a stable tuning dial / waterfall while the software actually adjusts its parameters to keep the beacons at a fixed frequency.

    (it would be best to do this in de demodulator and not by varying the LO frequency of the receiver, as that usually leads to momentary loss of lock)

    I also wasn't too disappointed by the stability of my PLL LNB (a much cheaper StarCom SR-3602, about 8 euro including shipping from China).

    Not good enough for digital modes but for SSB during quiet weather and with the hand on the dial it should so, better than LEO sats!

    In the meantime I have ordered an SR-3604 (4 outputs) to convert it to external LO injection, much more convenient to use one of the extra F connectors than to fix some extra input to this one.

    Peter, do you know if the beacon is transmitted on an antenna with that pattern, or of a broader beam (maybe a hemi like we will get) is being used?

    I was amazed to get 30dB S/N on the beacon, expecting an antenna pattern like the above.

    Or maybe that was during a test of the antenna pattern as you indicated above, when I listened earlier today it was a lot weaker.

    Yes, now it is updating on Celestrak as well!

    Code
    1. ES'HAIL 2
    2. 1 43700U 18090A 18332.22470325 .00000137 00000-0 00000+0 0 9994
    3. 2 43700 0.0925 247.3206 0001517 355.4163 289.2452 1.00275907 268

    Of course I understand... just a bit impatient to see the signal levels we will get from the transponder ;)

    If the beacon is any indication, it will be very good. I get its carrier at 30dB over the noise on my DTH TV dish which is not really optimal in performance.

    (of course the antenna gain for the beacon may be quite different from the antenna we get, but I am guessing it is also a broader pattern not like the pattern for the DTH transponders, which are quite weak here from the typical satellites operated for that region)

    Please understand that this is a multi-million commercial satellite and we are only a small part of it.

    Apparently those satellite operators are not like us. When we get a new box on the doorstep, we want to try it out, turn the dial, listen for the noise from the receiver, not run the extended selftest that takes a month to complete :)

    Perhaps, nothing has changed in the data of the orbit, so the TLE is not updated all this time?

    The TLE is not updated for some reason, but that reason is not that the orbit hasn't changed! The orbit has changed a lot and the TLE is totally invalid. And so is the tracking offered by sites like N2YO that use the TLE for their calculations.

    Nicest would be a project to construct a 13cm feed that can somehow fit around a satellite LNB. My LNB (and I think most of them) has a feedhorn diameter of 50mm which is a bit large to fit 13cm feeds.... but maybe someone has an innovative idea?